Glasses for Computer use.

Hi,
I'm blowing in to ask if anyone can advise me. A year ago I got my
first pair of reading glasses. I haven't been using them for computer
work but lately I've had trouble focusing on the screen and I've been
getting headaches. My reading glasses are too strong though and I
don't like using them on the computer, I've tried them a few times.

The screen is 24" (.61 m) from my eyes. My prescription is .125 both
eyes, nothing else. The optician said it was age typical presbyobia.
I don't want to pay another visit to the optician's just yet - next
time I go, and if I need new glasses I will get them for computer use
and get OTC readers for reading as I spend more hours doing the
former. But until then should I get .100 or .75? OTC readers for
computer work? And how do you work it out? I understand .100 means
lengthening the focal point one metre.

Graminator

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> Hi,
> I'm blowing in to ask if anyone can advise me. A year ago I got my
> first pair of reading glasses. I haven't been using them for computer
> work but lately I've had trouble focusing on the screen and I've been
> getting headaches. My reading glasses are too strong though and I
> don't like using them on the computer, I've tried them a few times.
>
> The screen is 24" (.61 m) from my eyes. My prescription is .125 both
> eyes, nothing else. The optician said it was age typical presbyobia.
> I don't want to pay another visit to the optician's just yet - next
> time I go, and if I need new glasses I will get them for computer use
> and get OTC readers for reading as I spend more hours doing the
> former. But until then should I get .100 or .75? OTC readers for
> computer work? And how do you work it out? I understand .100 means
> lengthening the focal point one metre.
>
> Graminator

I assume your reading Rx is +1.25 diopters since +.125 is too small of a
power bother with glasses, and most lenses only come in increments of .25.

Optometrists, like all doctors, take pride in their sloppy and illegible
handwriting (without the proper decimals), which is why you are confused
about the power.

I would just try on some OTC readers at the store, focusing on the same
distance as your monitor (take a tape measure with you), and pick out the
right power that way. Assuming that your reading Rx is +1.25, then your
guess of +.75 or +1.00 is probably correct for computer distance, but you
can easily verify that at the store.

(E-Mail Removed) wrote:
> Hi,
> I'm blowing in to ask if anyone can advise me. A year ago I got my
> first pair of reading glasses. I haven't been using them for computer
> work but lately I've had trouble focusing on the screen and I've been
> getting headaches. My reading glasses are too strong though and I
> don't like using them on the computer, I've tried them a few times.
>
> The screen is 24" (.61 m) from my eyes. My prescription is .125 both
> eyes, nothing else. The optician said it was age typical presbyobia.
> I don't want to pay another visit to the optician's just yet - next
> time I go, and if I need new glasses I will get them for computer use
> and get OTC readers for reading as I spend more hours doing the
> former. But until then should I get .100 or .75? OTC readers for
> computer work? And how do you work it out? I understand .100 means
> lengthening the focal point one metre.
>
> Graminator
>

I think you're slipping decimals. 1.00 Diopter means a focal length of
1 meter. Your Rx may be 1.25, but it could be .125, there is a huge
difference. The formula is 1/d=f where d=lens power in diopters and
f=focal length in meters.

On Mar 10, 2:05 am, Salmon Egg <salmon...@sbcglobal.net> wrote:

> I want to emphasize that I am not a medical person, but I do understand
> optics. Presuming your actual prescription is currently 1.25D as has been
> suggested by previous posters, your glasses should (approximately) make an
> object at a distance of 0.8 meter look as if it were at infinity. What you
> want is for your computer screen at 0.61m to look as if it were at infinity.

I would say that the goal of reading glasses is to supplement his
flagging accommodation in order to bring the plane of focus closer to
the retina, thereby reducing the area of blur or defocus.

DrG

On 3/10/07 5:54 AM, in article
(E-Mail Removed). com, "Dr. Leukoma"
<(E-Mail Removed)> wrote:

> On Mar 10, 2:05 am, Salmon Egg <salmon...@sbcglobal.net> wrote:
>
>> I want to emphasize that I am not a medical person, but I do understand
>> optics. Presuming your actual prescription is currently 1.25D as has been
>> suggested by previous posters, your glasses should (approximately) make an
>> object at a distance of 0.8 meter look as if it were at infinity. What you
>> want is for your computer screen at 0.61m to look as if it were at infinity.
>
> I would say that the goal of reading glasses is to supplement his
> flagging accommodation in order to bring the plane of focus closer to
> the retina, thereby reducing the area of blur or defocus.
>
> DrG
>
Does not what I suggested above do just what you say needs to be done?

Bill
-- Fermez le Bush--about two years to go.

On Mar 10, 9:44 pm, Salmon Egg <salmon...@sbcglobal.net> wrote:
> On 3/10/07 5:54 AM, in article
> 1173534895.551926.311...@q40g2000cwq.googlegroups. com, "Dr. Leukoma"
>
> <d...@leukoma.com> wrote:
> > On Mar 10, 2:05 am, Salmon Egg <salmon...@sbcglobal.net> wrote:
>
> >> I want to emphasize that I am not a medical person, but I do understand
> >> optics. Presuming your actual prescription is currently 1.25D as has been
> >> suggested by previous posters, your glasses should (approximately) make an
> >> object at a distance of 0.8 meter look as if it were at infinity. What you
> >> want is for your computer screen at 0.61m to look as if it were at infinity.
>
> > I would say that the goal of reading glasses is to supplement his
> > flagging accommodation in order to bring the plane of focus closer to
> > the retina, thereby reducing the area of blur or defocus.
>
> > DrG
>
> Does not what I suggested above do just what you say needs to be done?
>
> Bill
> -- Fermez le Bush--about two years to go.

Yes, Bill, but the devil is in the details. The conditions at
infinity are simply not the same for everybody, i.e. nearsighted folks
vs. farsighted folks.

Sure, I 'm being picky, but that's my job.

DrG

On 3/10/07 8:30 PM, in article
(E-Mail Removed), "Dr. Leukoma"
<(E-Mail Removed)> wrote:

> On Mar 10, 9:44 pm, Salmon Egg <salmon...@sbcglobal.net> wrote:
>> On 3/10/07 5:54 AM, in article
>> 1173534895.551926.311...@q40g2000cwq.googlegroups. com, "Dr. Leukoma"
>>
>> <d...@leukoma.com> wrote:
>>> On Mar 10, 2:05 am, Salmon Egg <salmon...@sbcglobal.net> wrote:
>>
>>>> I want to emphasize that I am not a medical person, but I do understand
>>>> optics. Presuming your actual prescription is currently 1.25D as has been
>>>> suggested by previous posters, your glasses should (approximately) make an
>>>> object at a distance of 0.8 meter look as if it were at infinity. What you
>>>> want is for your computer screen at 0.61m to look as if it were at
>>>> infinity.
<snip>
> Yes, Bill, but the devil is in the details. The conditions at
> infinity are simply not the same for everybody, i.e. nearsighted folks
> vs. farsighted folks.
>
> Sure, I 'm being picky, but that's my job.
>
> DrG
Presumably, the 1.25D he already uses takes care of spherical correction he
needs to compensate for his position along the myopia-hyperoia axis. The
remainder allows him to see his close computer display clearly. This is
simple physics--not complicated biology.

Bill
-- Fermez le Bush--about two years to go.

On Mar 11, 12:00 pm, Salmon Egg <salmon...@sbcglobal.net> wrote:

> Presumably, the 1.25D he already uses takes care of spherical correction he
> needs to compensate for his position along the myopia-hyperoia axis. The
> remainder allows him to see his close computer display clearly. This is
> simple physics--not complicated biology.

Simple physics assumes a linear 1:1 relationship between accommodative
stimulus and accommodative response. It also assumes that what the
patient perceives as clear is the same as having the circle of least
confusion exactly at the plane of the retina. If you are trying to
paint a mental picture, it's nice to be able to have an understanding
of the eye's physiology, which is physics and biology.

DrG

On 3/11/07 11:40 AM, in article
(E-Mail Removed). com, "Dr. Leukoma"
<(E-Mail Removed)> wrote:

> Simple physics assumes a linear 1:1 relationship between accommodative
> stimulus and accommodative response. It also assumes that what the
> patient perceives as clear is the same as having the circle of least
> confusion exactly at the plane of the retina. If you are trying to
> paint a mental picture, it's nice to be able to have an understanding
> of the eye's physiology, which is physics and biology.

Educate me if I am wrong. Do you not fit spectacles so that there is a
distance for which accommodation effort is not required? For example, does
an emmetropic eye use accommodation to view objects at infinity? Why not
design (fit) spectacles so that no accommodation is required at the working
distance to the display?

Bill
-- Fermez le Bush--about two years to go.

On Mar 12, 12:19 am, Salmon Egg <salmon...@sbcglobal.net> wrote:

>
> Educate me if I am wrong. Do you not fit spectacles so that there is a
> distance for which accommodation effort is not required? For example, does
> an emmetropic eye use accommodation to view objects at infinity? Why not
> design (fit) spectacles so that no accommodation is required at the working
> distance to the display?

The average amount of tonic accommodation for an average eye at
infinity, i.e. no stimulus to accommodation, is approximately 0.50
diopters. At 40 cm., or a stimulus of 2.50 diopters, the amount of
accommodation in a non-presbyope would be approximately 1.75
diopters. In an early presbyope, it may be 1.00 diopter of
accommodation. Therefore, in a patient with 1.00 - 1.25 diopters of
accommodation at 40 cm., should I give a 2.50 diopter add, or a 1.25 -
1.50 diopter add?

DrG